According to the W9 IRS instruction on page 3, about Line 4 Exemption, Generally, individuals (including sole proprietors) are not exempt from backup withholding. I read this to mean that if you are a sole proprietor you should select 'Subject to backup witholding', and this is what I put down for myself. Note I don't think this means the IRS will withold, but it just means you are not exempt.

I am also hitting this problem. Package.resolved file has not changed according to source control, yet xcode cloud errors out because it says the package.resolved file is out of date

I hit this issue too, but there was an easy fix. Just add an Entitlements file to your plugin (in my case the Notification Extension) and give it some dummy capability like Associated Domains. After that it will generate an entitlements file and associate it with the target (you can go to the target's build settings and type code signing to confirm). After adding this file the archive got pushed successfully to ASC

I hit this issue too, but there was an easy fix. Just add an Entitlements file to your plugin (in my case the Notification Extension) and give it some dummy capability like Associated Domains. After that it will generate an entitlements file and associate it with the target (you can go to the target's build settings and type code signing to confirm). After adding this file the archive got pushed successfully to ASC